1. Field of the Invention
The present invention relates to a design rule management method, design rule management program, rule management apparatus and rule verification apparatus.
2. Description of the Related Art
Design rules (hereinafter also referred to as just “rules” when necessary) are often used in designing with a CAD system (Computer Aided Design). The design rules are information composed of (including) a sort of conditions and relational expressions for determining a design parameter (hereinafter also referred to just as a “parameter” when necessary) which specifies a shape of each part. For example, the design rules are a condition which regulates an interval of components and a condition of a width of wiring.
When a shape of a part is changed on the CAD system, a rule verification is performed for checking whether or not a part-shape parameter, which is one of parameters which are being changed, violates a design rule.
As an example of the rule verification method for checking whether or not parameters necessary for a product designing violates a rule, in some commercially-supplied CAD systems, allowable ranges of mass property values of shape dimensions and weights are predefined as a rule on the CAD system so that the rule verification is automatically performed when a part shape is changed in the CAD system.
In a CAE (Computer Aided Engineering) system, if allowable ranges of parameters are predefined as a rule in an analysis program, a rule verification is performed on analysis data. A program performing a calculation by using a user interface of a table format and a script, known as a simple analytical calculation tool is also generally used in designing. When such a tool is used, a rule is predefined as a script so that a rule verification is also performed, similar to the above case of the analysis program.
There has been proposed an integrated parameter expression model by a university. For example, a technique disclosed in a non-patent document 1 is capable of expressing a product entity such as a part, its attribute and its activity (task) by linking via networks the product entity, the attribute and the activity which are involved in a product development. Non-patent document 1: “Proposition of Product Behavior and Topology Design Process Model for Reliability Design System,” by Kazuhiro Aoyama, Tsuyoshi Koga, Susumu Kinoshita, online: http://www.msel.t.u-tokyo.ac.jp/˜tsuyoshi-koga/B5.pdf, (accessed on Mar. 8, 2006)
In a conventional designing of a product, rules are described and managed in an individual system such as a CAD system, an analysis program, an analysis control program and a PDA (Product Data Management), and a rule verification is performed in each system. The conventional method has had the following disadvantages.
1. Each rule is only valid in its corresponding system, and thus it is difficult to describe and check a rule through the entire design data of those systems.
2. The rules are treated as different data in a different system, and thus it is difficult to maintain the rules through the systems.
The following is a specific example of the disadvantage 1. It is assumed that a rule “the size a11 of the part A >10 mm” is assigned to a product shape which has been modeled by a CAD system and the fixed number “10 mm” is based on an analysis parameter which is one of parameters resulted from an analysis of a different analysis program. In this case, a rule using such a fixed number is not available anymore when a design target or a design condition are once changed, which makes the rule incompatible. More specifically, because a rule used in a CAD system and a rule used in an analysis program are treated as different data in each other, a result from a condition change in the analysis program becomes difficult to be reflected in the CAD system for example.
Moreover, when it is necessary to modify a rule that has been deviated from an actual design target and design condition because of the disadvantage 1, the disadvantage 2 has further to be resolved. Because of these disadvantages, a rule verification system may not work properly after the rules are changed many times. In order to solve the above disadvantages, there has been desired a system that associates a plurality of rules, each of which is described in corresponding design support system, so as to integrally manages the rules and performs a rule verification in chains through the entire systems.